Remodeling of hepatic vascular changes after specific chemotherapy of schistosomal periportal fibrosis

Hepatosplenic schistosomiasis was the first human disease in which the possibility of extensive long standing hepatic fibrosis being degraded and removed has been demonstrated. When such changes occurred, the main signs of portal hypertension (splenomegaly, esophageal varices) progressively disappeared, implying that a profound vascular remodeling was concomitantly occurring. Hepatic vascular alterations associated with advanced schistosomiasis have already been investigated. Obstruction of the intrahepatic portal vein branches, plus marked angiogenesis and compensatory hyperplasia and hypertrophy of the arterial tree are the main changes present. However, there are no data revealing how these vascular changes behave during the process of fibrosis regression. Here the mouse model of pipestem fibrosis was used in an investigation about these vascular alterations during the course of the infection, and also after treatment and cure of the disease. Animals representing the two polar hepatic forms of the infection were included: (1) "isolated granulomas" characterized by isolated periovular granulomas sparsely distributed throughout the hepatica parenchyma; and (2) 'pipestem fibrosis' with periovular granulomas and fibrosis being concentrated within portal spaces, before and after treatment, were studied by means of histological and vascular injection-corrosion techniques. Instances of widespread portal vein obstruction of several types were commonly found in the livers of the untreated animals. These obstructive lesions were soon repaired, and completely disappeared four months following specific treatment of schistosomiasis. Treatment was accomplished by the simultaneous administration of praziquantel and oxamniquine. The most impressive results were revealed by the technique of injection of colored masses into the portal system, followed by corrosion in strong acid. The vascular lesions of non-treated pipestem fibrosis were represented...

Schistosoma mansoni: relocation of parasites to lungs from hepatic portal system in rodents.

The prevalence and development of adult worms in the lungs of mice and gerbils infected with Schistosoma mansoni was investigated. All infected BALB/c mice harbored the schistosomes in their lungs at 10-12 weeks post-infection, showing the distinct relocation of adult worms to the lungs, from the hepatic portal system. The male and female flukes from lungs of BALB/c mice were significantly smaller than those from livers. The percentage of gravid females in lungs was considerably lower than that in the livers. The number of eggs recovered from lungs of BALB/c mice and gerbils having lung female worms, however, was higher than that from animals without lung females, indicating egg deposition of lung females. The number of eggs detected in the brains correlated well with the number of eggs from the lungs in BALB/c and ICR mice. Out of 119 infected gerbils at 8 weeks post-infection, only two animals had egg-emboli in the brain vessels, although many eggs embolized in the lungs of those animals. These data suggest that transfer of worms to the lungs from livers involves reduction of worm recovery from the portal circulation, and also pulmonary pathology of the disease.

Schistosoma mansoni: evoluçäo de vermes oriundos de cercárias irradiadas a nível de sistema porta, no camundongo / Schistosoma mansoni: development of worms from cercaria irradiated at the porta system level, in mice

Oito grupos de camundongos albinos (Mus musculus), näo isogênicos, foram infectados transcutaneamente com cerca de 450 cercárias (das cepas LE e SJ do S. mansoni), irradiadas com 3 Krad, 20 Krad e 40 Krad de radiaçäo gama proveniente de cobalto-60, e näo irradiados (grupos-controle). Os vermes provenientes de carcárias irradiadas com 20 e 40 Krad só foram encontrados em quantidades insignificantes no sistema porta. Verificou-se que os vermes irradiados com 3 Krad, que alcançam o sistema porta, mostram nítido retardo no desenvolvimento evolutivo quando comparados com os grupos-controles näo irradiados. Os vermes da cepa SJ (irradiados ou näo) têm evoluçäo mais lenta do que os da cepa LE

Schistosoma mansoni: aspectos quantitativos da evoluçäo de cercárias irradiadas a nível da pele, pulmöes e sistema porta, em camundongos / Schistosoma mansoni: quantitative aspects of the development of irradiated cercariae in the skin, lungs and portal system, in mice

Foi estudada a migraçäo do Schistosoma mansoni (cepas LE e SJ) em oito grupos de camundongos albinos (Mus musculus) näo isogênicos, infectados transcutaneamente com cerca de 450 cercárias näo irradiadas (grupos controles e irradiadas com 3 Krad, e 40 Krad de radiaçäo gama proveniente de cobalto-60. Na pele, observou-se uma diminuiçäo progressiva das taxas de recuperaçäo em funçäo do tempo e, nos pulmöes e sistema porta, verificou-se uma relaçäo inversa significativa entre as taxas de recuperaçäo total e as doses de irradiaçäo. A dose de 20 Krad praticamente impede a migraçäo dos parasitos, de ambas as cepas, dos pulmöes até o sistema porta, enquanto a de 40 Krd praticamente impede a migraçäo dos mesmos da pele para os pulmöes